Submarine drilling platform



y 1954 H, J. SCHAUFELE 2,677,935

SUBMARINE DRILLING PLATFORM Filed Feb. 11, 1950 5 Sheets-Sheet l A rTOKNE y- May 11, 1954 H. J. SCHAUFELE 2,677,935

SUBMARINE DRILLING PLATFORM Filed Feb. 11, 1950 5 Sheets-Sheet 2 V I I III i w m 39 39 I I s I I I 9: v

J JNVENTOR. HERBERT l]. lsdmuFiLE May 11, 1954 H. .1. SCHAUFELE2,677,935 SUBMARINE DRILLING PLATFORM Filed Feb. 11, 1950 5 Sheets-Sheet5 IN V EN TOR. HERBER T J Sal-In UF'EL E ATTORNEY.

y 1954 H. J. SCHAUFELE SUBMARINE DRILLING PLATFORM 5 Sheets-Sheet FiledFeb. 11, 1950 INVENTOR. UFELE HERBERT (I SCH!) May 11, 1954 H. J.SCHAUFELE 2,677,935

SUBMARINE DRILLING PLATFORM Filed Feb. 11, 1950 5 Sheets-Sheet 5 WH'TERLEVEL 1N VEN TOR.

HERBERT JCHHUFI'LE A TTORNE y.

, others have devised Patented May 11, 1954 Herbert J. Schaufele, Lon

to Signal Oil and .Gas

Califi, a corporation of g Beach, Calif., assignor Company, LosvAngeles, Delaware Application February'll, 1950, Serial No. 143,681

19 Claims. I

This invention relates to a structure for submarinedrillin platforms,including in the term submarine the bottoms under oceans, :seas, bays,harbors, roadsteads, lakes, estuaries, and other waters where suchstructures are .to be erected.

The-problem'of devising a drillingplatformto be erected in submarinebottoms which can be economically erected on a drilling site and whichwill form a .safe and stable platform in heavy weather has not, to.applicants knowledge, been satisfactorily solved. Efforts have beenmade to devise structures which may be erected at the site, others haveused structures of prefabricated sections which may beassembled at thesite, and structures which may be prefabricated and transported as aunit. Various means of transportation over water and methodsfor-erection at-the site have'been suggested. In some, the units aretransported on barges and pontoons and others have employed flotationtanks.

I have devised an improved, simple, and relatively inexpensive structurewhich 'may be fabricated and floated to the marine locations and erectedto form a stable drilling base which may be used either for a single orfor a multiple well location. The structure may be of minimum heightsuilicient 0 raise the deck of the platform above wave action so as topermit waves to pass underneath the deck without exerting any'seriousuplifting force on the deck structure and present a minimum surfaceagainst which wave pressure may be exerted. Means are provided whereby astable foundation may be formed for the structure.

The structure of my invention consists of a plurality of verticalmembers with suitable bracsubstantial size extending from near the topto'near the bottom of the structure. The conduit extends longitudinallyof the column and maybe closed at the bottom and if desired at the topto form an elongated chamber extending longitudinally of the column.Means may be provided to flood conduit with water to control thebuoyanceof the system. Additional buoyancy control means are providedwhich also will act to adjust the center of gravity of the structure.Thus a buoyancy tank is provided near the bottom of the structureand'means are provided to flood the lower tank with water to control thebuoyancy and center of gravity.

The conduit also may .be used as a means for erecting and stabilizingthe construction. Thus means ar provided for opening the bottom end ofthe conduit and for passing'excavating means through the conduit'toremove mud and earth from beneath the structure to permit of forming agood footing for thestructure. The conduit also makes it possible tointroduce cement for the purpose of establishing a foundation for-thestructure.

As a. permissible and, -I believe, highly-desirable feature, I make thebottom of the tank wedgeshaped; thus'it may be'conical. I intersect theconical bottom of the tank with the conduit. Thus, inelfect,'the'bottom.forms=a flared mouth for the conduit and thus :thecement forms a footing for the structure.

This stabilizing means, which, if desired, may be added to by means ofpiling driven through the tubular vertical members of the structure,stabilizes the'structure'in an economical, simple and eflicient'manner.The structure is thus stable and also removable. Thus, the'-structuremay be removed from the well site by cutting the piles and afterunloading the tanks and -buoyancy conduit, the structure may befloated-off its concrete base. The vertical members, if tubular, mayalso be used-as jet pipes to assist in the'erecting of the structure,and also when thestructure is to be removed, they assistiinbreaking theadhesion of the structure'in'the-earth or mud, and in freeing it andthus in the removal thereof.

These and other objects of my invention will be further described byreference to the drawings, in which Fig. 1 is an elevation of mystructure;

Fig. 2 is an irregular section taken on line 2-2 of Fig. 3;

Fig. 3 is a plan view;

Fig. 4 is a section taken-on :line 4-4 of Fig. 2;

Fig.5 is a'section taken'on line 55 ofFig. 2;

Fig. 6 is a section taken-on linet-G of Fig. '2;

Fig. '7 is a detail of Fig. 1;

Fig. 8 is a section similar to Fig. 2 but showing the superstructure;

Fig. 8a is a fragmentary section of the leg structure with the pile inposition; and

Figs. 9 to 15 show various stages in the erection of the drilling towerof my invention.

The structure as shown in Fig. 1 comprises a ring of tubular verticalleg :members I. They surround a centrally disposed vertical caisson -2.The members I are connected to the caisson 2 by means of radial braces 4(Fig. 5) and chordal bracing members 3 (Figs. land 5) at severalverti'cally spaced planes along the vertical memhere. At the top of thestructure the floor 6 is supported on the members I by means "of apreand lower frame membefore erection does not 5, 5 and 6 and fabricatedtruss bracing bers 5. The structure carry the deck superstructureappears as indicated in Fig. 1.

At the bottom of this structure I provide a tank having an inclinedbottom at an acute angle to the center line of the structure and of thecentral caisson 2. Where, as in the form shown in Fig. 2, the tank isdisposed across the whole bottom and is annular, the bottom may beconical.

Thus, as is shown in Fig. 1, the tank is circular in section andencompasses the vertical members I with the caisson 2 centrally disposedof the annular tank so that the caisson passes through the centralopening of the tank. The bottom I is conical in the shape of a truncatedcone intercepted by the central caisson 2. The bottom of the tank isthus a flared opening connected to the central caisson 2. The tank isprovided with a dome-shaped doughnut top 8 and sides 9. Verticalconduits l0 pass through the tank and the bottom '1 and top 8, making awater-tight connection with. said top and bottom. The tank is internallybraced by means of suitable angular bracing IE and radial bracings l2and chordal bracing H3. The lower corner of the tank formed by thejuncture of the bottom 1 and the side 9 is reinforced by a hardenedring-cutting shoe 9 which is welded to the bottom and sides of the tank.

The top of the central caisson 2 is closed by a removable bonnet Illsuitably bolted by means of flanges to the caisson 2. Inside the caisson2 and underneath the bonnet M I provide a spider l5, and near the bottomof 2 I provide a circumferential ring IS welded to the interior of thecaisson 2. Spaced 90 apart I weld locking brackets I! underneath thering I5. The brackets I! carry stops in the form of dependingperpendicular edge ridges l8 and is.

The locking spider 20 has four arms 2! spaced 90 apart, each arm havingan upstanding edge 23. A central hub 22 is also provided. The spideredge 23 fits inside the ridge l8 and abuts against the ridges [9.

A valve member 23 in the form of a dished plate having a downwardlyformed lip 24 and a hub 25 is placed on the ring it. The ring [6 and thedished plate form a water-tight seal when the dished plate is clampedagainst the ring. To effect this clamping action, a stud 26 is welded orotherwise rigidly affixed in the hub 22 and passes through the hub 25. Awheel 28 is screwed onto the stud 2s and locked in place by nut 26awhich is screwed on top of the stud 26. A pipe 29 is welded to the wheel28 and is j ournalled in the hub 33' of the top spider l5. A shoulder 3|on the pipe 23 bears on top of the hub 30. A plug 31 with a square headis spot welded or otherwise secured to the top of the pipe 29.

A line 32, opening to atmosphere or water, is connected near the base ofthe caisson 2 above the plate 23'. A valve 33 on line 32 is actuated bya long rod 34 journalled near the top of the caisson 2 in a bracket 35and actuated by a wheel 31.

Spaced 90 apart and positioned near the bottom corner where the bottom 1joins the side 9 are four pipes 33 also opening to atmosphere or thewater and having a valve 39 actuated by a long stem C 0 suitablysupported at the top of the structure and actuated by a hand wheel 4|.Four air vent lines 42 ar connected 90 apart to the top of the convexdoughnut-shaped roof 8 of the tank. Each line carries valve 43. A valvedair vent M is positioned in the bonnet l4. This construction results inan elongated buoyancy chamber extending longitudinally of the structureand disposed centrally thereof, with a removable closure near the lowerend thereof and a closure at the top thereof.

To erect the structure which may be assembled on shore, the structure asshown in Fig. 2 and as described, with the superstructure 5, 5, and 6removed, is assembled with the valve disc 23' in clamped positionagainst ring [6 and with bonnet M in position and valves 33, 38, 43, and44 closed and the plugs I in position. The structure is floated on itsside (see Fig. 10).

In employing the plugs l, the leg members I are thus partly filled withwater but retain a large air chamber which thus acts to add buoyancy tothe structure. However, with a sufficiently large caisson or tank, thisadded buoyancy is not necessary. I, therefore, in such case, omit theplugs I and instead, while the structure is on shore or after it isfloated, I thread the piles 46 to be employed through the tubular legs Iso that the ends of the piles are Within and close to the end of thelegs I. The piles which are preferably tubular are held in position inthe legs I by a bolt 41.

The buoyancy of the structure is attained by reason of the air filledlower tank and caisson 2. The size of the chamber and pipes ispreferably, but not necessarily, such that the caisson 2 floats in thewater in a horizontal position.

The caisson terminates above the bottom of the structure. In order toprovide buoyancy for the lower end of the structure the bottom tank isprovided. It will also be observed that the structure is symmetrical andwill float on even keel.

When the structure is towed to the desired location I may, by means ofthe tow line or by bottom anchor, hold the structure in approximatelythe desired location. If desired I may employ a derrick barge so thatthe hoist line of a boom derrick may be connected to the top of thestructure. The valves 38, which are submerged, are opened and the valve43 on the line which is in the air is opened. Water enters the lowertank and the tank end of the structure sinks. As the caisson becomescovered with water its buoyancy increases and the upper end of thestructure emerges from the water, unless water is admitted to thecaisson to control the buoyancy.

Since, as is desirable, the lower tank is of limited capacity,determined primarily by the requirement designed to add flotationcharacteristics to the lower end of the structure below the end of thecaisson, and due to the large buoyancy of the chamber of the caisson 2,it will be desirable to flood a portion of the volume of caisson 2 inaddition to the flooding of the lower tank. This is accomplished byopening valve 33 and bleeding air through 44. Water enters into the tankand caisson and its rise is controlled by the bleeding of the airvalves. The structure thus pendulums about its center of buoyancy aboutthe boom, if that is employed, and floats vertically in the water. Thepercentage of the structure so immersed is determined by the amount ofwater entering the tank and particularly the caisson 2.

It is to be observed that it is desirable when this is accomplished thatthe structure in its vertical position be off bottom.

It will also be observed that when this is accomplished the water levelin the caisson 2 will be below the water line, and the air thus be undersome hydrostatic pressure, that is, there is residual buoyancy in thetank.

The degree of buoyancy may be additionally controlled by connecting thevalve 54 and line 42 to valve 43 to an air compressor on the barge sothat air may be bled from caisson 2 and tank, or air introduced to blowout some of the water in the caisson or tank. In this way the structuremay be held off bottom in a floating and vertical position steadied, ifdesired, by bottom anchors or tow lines or a derrick boom 45.

With the structure in such position, the plugs I, if used, are removedand piles 4t are dropped through the tubular members i. If the pileshave been previously threaded through the lugs, the bolts 47 areremoved. With the structure floating in a vertical position or with thepiles held in a vertical position, the piles are driven into thesubmarine bottom by means of a pile driving or derrick barge anchoredalongside the structure. It will be observed that the feature of thisinvention whereby the piles are carried in threaded position in the legsis a highly advantageous one. For example, if the structure requires 100to 200 feet of pile and is riding 2G to 50 feet out of the water, theproblem of upending and lifting a 120-foot pile so its lower end is 20to 50 feet and threading this through the leg in an open body of water,presents a practioal difficulty in operation. This is avoided by theproposed method of pre-threading the pile while the structure is on itsside.

After the piles are driven, air is now bled from the tank, if it is notfull of water, and from the caisson 2, and the structure settles gentlyas the air is bled down. ii'he piles guide it as it settles verticallyon bottom. If desired, especially if a suilicient number of legs areemployed so that they are not all necessary for guide members for thepiles, I may, by suitably arranging the piles, employ certain of thelegs distributed about the periphery of the shoe 9' as jet pipes to jetWater or air to assist in the setting of the structure.

When the seat bottom is not flat or is muddy, I may, because of thepeculiar design of my structure, which is particularly designed topermit of this function. excavate from underneath the structure.

This is accomplished by removing the bonnet i4. By applying a wrench tothe head 3i, I may rotate the pipe 29 and the wheel 28. The hand wheelrides up the stud (loosening the clamp on the valve disc 23) until itrides up against the collar 26. A further quarter rotation moves thespider from underneath the brackets ll. It will be observed that thespider arms 2.! cannot be entered underneath the bracket 11 by thefurther rotation of the hand wheel because 01" the ridges IS. In thisposition the spider i is loosened and the spider l5, pipe 29, and thevalve closure 23 and spider it! may be withdrawn from caisson 2.

An excavating tool, as, for example, a clam shell or orange peel bucket,may then be lowered through the caisson from a suitably anchored derrickbarge. The piles will hold the structure in position against lateraldisplacement.

The bucket excavates underneath the bottom aided by the sluicing effectof the sea. When sufiicient excavation has occurred to form the desiredbottom to act as a foundation for the structure, ,I may remove theexcavating -cquip- This dimension is given.

ment. It will be observed that as I excavate the structure will settlevertically on the piles and the cutting edge of the shoe 9' will cutinto the earth. I remove the excavating bucket and introduce concreteinto the caisson 2 so that it discharges from the end of the caisson andfills, in underneath the conical bottom I. If the sea bottom is slopingor if there is any unevenness, concrete may discharge underneath theedge 9 to create a concrete cone on the bottom on which the structurerests.

It will be observed that the caisson is made of suiiicient size for thispurpose. In order to indicate the order of magnitude of the caisson andto illustrate, it will pass conventional grab bucket equipment used forexcavation. I may mention that for the structure illustrated, I may usea caisson 8 feet in diameter, more or less. not by way of limita tionbut to illustrate the order of magnitude of the structure and itsmultiple functions.

In order to increase the stability of the structure I may unwater thetank by means of compressed air blown through lines 42 and by openingvalves 39, and then closing the valve. Mud or heavy weighting fluid maythen be introduced through certain of the lines 42 into the bottom tank,valves 33 being closed, and other of the lines 42 acting as air vents.The stability may also be increased by reintroducing the spider I5, pipe25, and the cover plate 23, and spider 20, and locking spider 20 andclamping the cover plate against the plate i 6 by rotating the head 3|so as to rotate the spider underneath the brackets il beside the ridgei8 and against the ridge 5 9, and clamping the plate by further rotationof the wheel. Weighting mud may then be run into the central caisson.

It is not my purpose, especially, as will be described below, when it isdesired that the structure is to be made removable, to cause the cementto rise any material distance up the caisson 2. However, some cementtends to rise up the conduit iii. If desired, therefore, the surfaceconductor casing i of the oil wells to be drilled from the structure,may be first set in the conduit it), held vertically and driven into theearth, and the concrete poured via 2, thus rising in It and around thesurface to hold the casing for use in drilling.

It will be observed that the cement cone acts with the piles and thecemented surface conductor pipe to act as a stabilizer.

If the structure is to be removed, for example, when it is used for oilwell drilling and no oil field is found, or if it becomes exhausted andit is desired to move'the structure away, this may be done relativelysimply. The equipment on the deck and superstructure formed of thebracings 5i, 5 and deck supporting the deck are removed. A bottom anchoror a derrick barge is used to steady or remove the structure after it isreleased in a manner similar to that employed in erecting the same. Ifno cement is in the caisson 2 above the ring iii, the valve member maybe placed in position by introducing the spider pipe '2 9, and disk 23and. clamping spider 26. The rotation of the pipe 29 clockwise willenter the clamping spider underneath the brackets 5?, as describedabove, and continued rotation of the pipe 25 will clamp the disk 23'against the ring iii. A conventional inside cutter is run in the surfaceconductor pipes s and they are cut off at or near the mud line. Thetubular piles ii; are cut oil at themud line by dropping a charge ofpowder .on

an electrical line to the bottom of the piles at the mud line,electrically firing the charge. This will cut off the piles beyond theend of the legs I. The released conductor pipes and the piles may thenbe removed. The mud, if any in the tank, may be discharged in many ways,as, for example, by introducing compressed air through lines 42 anddischarging the mud through valves 38. When the mud is discharged thevalves are closed.

The water may be discharged from the caisson 2 by replacing the bonnetl4 and introducing air under pressure via valve 44, water dischargingvia valve 33. When air breaks through, valve 33 is closed. As the waterand mud are discharged from valves 39 and 33, and the buoyancy of thestructure increases, a point will be reached when the structure startsto float. If the adhesion of the structure against the mud and thecement hinders the release of the structure, a water or air line may beconnected to the top of the legs 1, as by welding on the fluid line, andair or water jetted underneath the conical bottom and the shoe 9 tobreak the adhesion of the mud or earth against the surfaces of thestructure and assist in the removal of the structure.

If it is desired to make the structure perma nent, the tank may befilled with cement via the line 32, and, if desired, also the caisson 2may be filled with cement or with reinforcing members anchored to theearth when forming the cone bottom.

While I have described as a preferred embodiment a structure with acentral caisson having top and bottom closures, I may omit the bottomclosure and employ auxiliary flotation tank positioned at the top of thestructure. In such construction I sacrifice the advantage of employingthe caisson as a flotation tank, but do preserve the other advantages ofthis structure. For this reason, I believe the structure described inthe application in which a bottom closure for the central caisson isemployed, is a preferred structure.

While I have described a particular embodiment of my invention for thepurpose of illustration, it should be understood that variousmodifications and adaptations thereof may be made within the spirit ofthe invention as set forth in the appended claims.

I claim:

1. A portable submarine structure, which comprises a plurality oftubular members having their interiors unobstructed and their wallsimperforate, an elongated vertically disposed caisson, the exterior wallof said caisson and the exterior wall of said tubular members beingconnected, a removable closure for both ends of said caisson, means forflooding said caisson with water, between said closures, to control thebuoyancy thereof, a buoyancy tank disposed at the lower end of saidcaisson, and means for independently flooding said buoyancy tank tocontrol the buoyancy of the tank independently of said caisson.

2. A portable submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofvertical tubular members having their interiors unobstructed and theirwalls imperiorate, an elongated vertically disposed tubular caisson,said caisson having imperforate side walls connected to said members, aremovable closure for both ends of said caisson, means for flooding saidcaisson with water to control the buoyancy thereof, a buoyancy tankdisposed at the lower end of tending from the upper 8 I said caisson,means for flooding said buoyancy tank with water to control the buoyancythereof, and a flared conical bottom to said tank, said conical bottomcommunicating with the caisson below the said closure.

3. A portable submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofunitary vertical imperforate tubular members open throughout theirlength, an elongated vertically disposed caisson having an imperforateand tubular wall and open at each end and connected to said members, aremovable closure for both ends of said caisson, means for flooding saidcaisson with water to control the buoyancy thereof, an annular buoyancytank, said caisson being centrally disposed of said tank in the centralopening thereof, and conduits passing through the top and bottom of saidtank.

4. A portable submarine structure adapted to support a. drillingplatform at an elevation above the water line, which comprises aplurality of vertical tubular members, the walls of which areimperforate and continuous from approximately the bottom to the top ofthe structure, an elongated vertically disposed caisson connected tosaid members, a removable closure for both ends of said caisson, meansfor flooding said caisson with water to control the buoyancy thereof, anannular buoyancy tank, said caisson being centrally disposed of saidtank in the central opening thereof, a conical bottom for said tank,said conical bot tom forming a flared mouth for said tank, a conduitpassing through the to and bottom of said tank, a ring mounted near thelower end of said caisson, a disk mounted on said ring to close the endthereof, a clamping member for holding said disk tightly on said ring,and a member connected to said clamping member and extendinglongitudinally of said caisson and actuable from the upper end thereoffor manipulating said clamping members.

5. A portable submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofvertical tubular members open throughout and continuous for their fulllength and the walls of said tubular members being imperforate, avertical caisson having an imperforate tubular side wall, removableclosures for the top and bottom openings of said caisson, means forflooding said caisson between the said closures to control the buoyancyof said caisson, said caisson being centrally disposed of said verticalmembers and exto the lower part of said structure, a tank positioned atthe lower end of said members, a flared mouth for said central caissonat the lower end thereof, and means for flooding said caisson and saidtank with water.

6. A portable submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofvertical members open throughout their length and having imperforatewalls throughout their length, a. vertical caisson centrally disposed ofsaid vertical members and having an imperforate wall throughout thelength thereof and extending to a flared mouth for said central caissonat the lower end thereof, and a tank positioned at the lower end of saidmembers, said flared mouth forming the bottom of said tank.

7. A portable submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofvertical members, a vertical caisson centrally disposed of said verticalmembers and extending from the upper to the-lower part of saidstructure, said vertical members and said caisson having imperforatewalls, said vertical members and said vertical caisson being joinedtogether by structural members attached to their outer walls, aremovable closure for the upper endof said caisson, means for floodingthe caisson below said closure, means for unwatering said caisson belowsaid closure to control the buoyancy of said caisson, a tank positionedat the lower end of said members, means to floor said tankwith water,means to empty said. tank of said flooding water, and a flared mouth forsaid central caisson at the lower end thereof, said flared mouth and thelower part of said caisson formingapluraiity of the walls of said tank.

8. A buoyant submarine drilling platform structure adapted for erectionon a submarine bottom, to ,supporta drilling platform above water, whichcomprises a plurality of vertical members, a deck structure connected toone end of said members, an elongated caisson extending along andadjacent to said vertical members, the lower end of said caisson beingadjacent the lower end of said vertical members, cross-bracing betweensaid members and said caisson, an auxiliary flotation tank positionedadjacent the lower end of said caisson, and bracing connection betweensaid tank and said vertical members.

9. A buoyant submarine drilling platform structure adapted for erectionon a submarine bottom to support a drilling platform above water, whichcomprises a plurality of vertical members, a deck structure connected toone end of said members, an elongated caisson extending along andadjacent to said vertical members, the lower end of said caisson beingadjacent the lower end of said vertical members, cross-bracing betweensaid members and said caisson, an auxiliary flotation tank positionedadjacent the lower end of said caisson, bracing connection between saidtank and said vertical members, and a removable closure for said caissonpositioned near one end of said caisson.

10. A buoyant submarine drilling platform structure adapted for erectionon a submarine bottom, comprising a plurality of elongated leg members,a deck structure connected to one end of said leg members, an elongatedcaisson extending along and adjacent said elongated leg members, thelower end of said caisson being adjacent the lower end of said legmembers, a removable closure at one end of said caisson, a removableclosure at the other end of said caisson, and an inlet pipe connectionand an outlet pipe connection connected to said caisson between saidclosures.

11. A buoyant submarine drilling platform structure adapted for erectionon a submarine bot-tom, comprising a plurality of elongated leg members,a deck structure connected to one end of said members, an elongatedcaisson extending along and adjacent said members, the lower end of saidcaisson being adjacent the lower end of said members, a removableclosure at one end of said caisson, a removable closure at the other endof said caisson, an inlet pipe connection and an outlet pipe connectionconnected to said caisson between said closures, a flotation tankpositioned adjacent the ends of said caisson and elongated members, andan inlet pipe connection and outlet pipe connection connected to saidtank.

12. A buoyant submarine drilling platform structure, comprising aplurality of elongated vertical-members, adeck structure connected-toone end'ofsaidmembers, an elongated caisson extending adjacent to andalong said vertical members, a flared'mouth at one end of said caissonandextending beyond the ends of said vertical members, and cross-bracingbetween said vertical members and said caisson.

13. A buoyant submarine drilling platform structure, comprising aplurality of elongated vertical members, a deck structure connected toone end-of. said'membe-rs, an elongated'caisson extending adjacent toand along said vertical members, a flared mouth at one end of saidcaisson and-extending beyond the ends of saidverticalmembers,cross-bracing between said verticalmem-bers and said caisson, and aremovable closure for said'caisson positioned near one end of saidcaisson andabove said flared mouth.

14. A- buoyant submarine drilling platform structure, comprising aplurality of elongated vertical members, a deck structure connected toone end of said members, an elongated caisson extending adjacent andalong said vertical members, a flared mouth at one end of said caissonand extending beyond the ends of said vertical members, cross-bracingbetween said vertical iembers and said caisson, a removable closure forsaid caisson positioned near one end of said caisson and above saidflared mouth, a removable closure at the other end of said caisson, andan inlet and an outlet connection to the caisson between said closures.

15. A submarine drilling platform erected on a submarine bottom,comprising a plurality of elongated vertical members extending above thewater, a drilling platform positioned on said members above the waterline, a caisson extending adjacent to and along said members, crossconnections between said members and said caisson, a flared mouth at oneend of said caisson, said flared mouth positioned on said submarinebottom, concrete positioned in said flared mouth and on said submarinebottom, and piles driven through said elongated vertical members andinto the submarine bottom.

16. A submarine drilling platform erected on a submarine bottom,comprising a plurality of elongated tubular Vertical members extendingabove the water, a drilling platform positioned on said members abovethe water line, a caisson extending adjacent to and along said members,one end of said caisson positioned on said submarine bottom, crossconnections between said members and said caisson, concrete positionedin said end and on said submarine bottom, and piles driven through saidelongated vertical tubular members and into the submarine bottom.

17. A buoyant submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofvertical tubular members, an elongated vertically disposed caissonconnected to said members, removable closure for both ends of saidcaisson, an inlet and outlet connection for flooding said caissonbetween said closures, with water to control the buoyancy thereof, and aflared conical mouth connected to said caisson below said closure.

18. A buoyant submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofvertical members, a deck structure connected to one end of said members,a vertical caisson centrally disposedof said vertical members andextending from the upper to the lower part of said structure, saidvertical members and said vertical caisson having imperforate walls, aremovable closure for the upper end of said caisson, means for floodingthe caisson below said closure, means for unwatering said caisson belowsaid closure to control the buoyancy of said caisson, and a flared mouthat the lower end of said central caisson.

19. A buoyant submarine structure adapted to support a drilling platformat an elevation above the water line, which comprises a plurality ofvertical tubular members, a vertical caisson centrally disposed of saidvertical members and extending from the upper to the lower part of saidstructure, said tubular members having imperforate walls and beingunobstructed throughout their length, a removable closure for the upperend of said caisson, means for flooding the caisson below said closure,means for unwatering said caisson below said closure to control thebuoyancy of said caisson, a

tank positioned at the lower end of said members, and a flared mouth forsaid central caisson at the lower end thereof.

5 References Cited in the file or this patent UNITED STATES PATENTSNumber Name Date Plummer Sept. 5, 1939 Voorhees Jan. 23, 1940 Kirby June10, 1947 Shannon Dec. 19, 1950 Guenzel Jan. 1, 1952 Parks Apr. 1, 1952FOREIGN PATENTS Country Date France of 1875 Italy of 1927 OTHERREFERENCES Eng. News-Record, page 842, June 13, 1935.

